I have two reasons why my gaming in general has dropped dramatically.
One is increased distractions from other devices and entertainment sources vying for my attention. Between my smart phone and iPad, NetFlix and then the constant interaction that comes with social media sites, my attention is constantly pulled away from console gaming. I use my PS3 to watch NetFlix movies 90% of the time and gaming the other 10%.
My other issue is games have become boring in the PS3/XBOX 360 generation of gaming. My guess is all the creativity and man-hours are going into making the games look and sound good, so nothing is left over to go towards intriguing game-play. If game play sucks, I'm not going to waste my time. I think Portal also ruined a lot of games because of the pressure for developers to stick puzzles in everything. Blech! I'm having a great old time blasting aliens, and then all the fun stops because I have to figure out a dumb puzzle. Also, there's too much instructions in games now -- thanks to Mario Bros games. Blech! Instructions, puzzles in non-puzzle games and run-on-rails gameplay have killed gaming for me.